Driver door won't open from outside

I'm having an issue during the cold weather where the driver door won't open from the outside. I'm having to climb over from the passenger seat to open it from the inside. It will then open okay from the outside after closing until I lock the door again and repeat.

I've tried the manual key slot but that doesn't work either. Holding the key fob doesn't lower the windows (is this not a feature on 2009 models?) Pouring warm water over the door hasn't helped so it doesn't seem to just be frozen.

Any ideas on a way to get it working again? The fact it is still an issue when it's defrosted suggests it may not resolve itself